Antioxidant activity of isocoumarins isolated from Paepalanthus bromelioides on mitochondria

The isocoumarins (1-50 mu M) paepalantine (9,10-dihydroxy-5,7-dimethoxy-1H-naptho(2,3c)pyran-1-one), 8,8 '-paepalantine dimer, and vioxanthin isolated from Paepalanthus bromelioides, were assessed for antioxidant activity using isolated rat liver mitochondria and non-mitochondrial systems, and compared with the flavonoid quercetin. The paepalantine and paepalantine dimers, but not vioxanthin, were effective at scavenging both 1,1-diphenyl-2-picrylhydrazyl (DPPH*) and superoxide (O-2(-)) radicals in non-mitochondrial systems, and protected mitochondria from tert-butylhydroperoxide-induced H2O2 accumulation and Fe2+ -citrate-mediated mitochondrial membrane lipid peroxidation, with almost the same potency as quercetin. These results point towards paepalantine, followed by paepalantine dimer, as being a powerful agent affording protection, apparently via O-2(-) scavenging, from oxidative stress conditions imposed on mitochondria, the main intracellular source and target of those reactive oxygen species. This strong antioxidant action of paepalantine was reproduced in HepG2 cells exposed to oxidative stress condition induced by H2O2. (C) 2007 Elsevier Ltd. All rights reserved.

High-performance liquid chromatographic separation and identification of polyphenolic compounds from the infusion of Davilla elliptica St. Hill

The isolation of polyphenolic compounds from an infusion of the Brazilian plant Davilla elliptica (Dilleniaceae), used as tea by virtue of its digestive properties, is described. An improved preparative HPLC method was used in order to isolate pure polyphenols from the complex mixture. Liquid-liquid extraction and solid-phase extraction were employed to minimise the interference of polymeric compounds and to provide an enriched fraction of the compounds of interest. The identification of the isolated compounds was performed using analytical HPLC as well as direct injection electrospray ionisation ion trap tandem mass spectrometry (ESI-IT-MS/MS). The high flavonoid content suggests that D. elliptica may be a promising source of compounds to produce natural phytomedicines. Copyright (C) 2007 John Wiley & Sons, Ltd.

Hepatoprotective and anti-inflammatory effects of silibinin on experimental preeclampsia induced by 1-NAME in rats

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Inhibitory effect of silibinin on tumour necrosis factor-alpha and hydrogen peroxide production by human monocytes

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Black bean (Phaseolus vulgaris L.) as a protective agent against DNA damage in mice

This study was designed to evaluate the toxicogenetic or protective effect of cooked and dehydrated black beans (Phaseolus vulgaris L.) in bone marrow and peripheral blood cells of exposed mice. The frequency of micronuclei detected using the bone marrow erythrocyte micronucleus test and level of DNA lesions detected by the comet assay were chosen as end-points reflecting mutagenic and genotoxic damage, respectively. Initially, Swiss male mice were fed with a 20% black bean diet in order to detect mutagenic and genotoxic activity. However, no increase in the frequency of bone marrow micronucleated polychromatic erythrocytes (MN PCEs) or DNA lesion in leukocytes was observed. In contrast, received diets containing 1, 10 or 20% of black beans, a clear, but not dose-dependent reduction in the frequency of MN PCEs were observed in animals simultaneously treated with cyclophosphamide, an indirect acting mutagen. Similar results were observed in leukocytes by the comet assay. Commercial anthocyanin was also tested in an attempt to identify the bean components responsible for this protective effect. However, instead of being protective, the flavonoid, at the highest dose administered (50 mg/kg bw), induced primary DNA lesion, as detected by the comet assay. These data indicate the importance of food components in preventing genetic damage induced by chemical mutagens, and also reinforce the role of toxicogenetic techniques in protecting human health. (C) 2003 Elsevier Ltd. All rights reserved.

Anti-coagulase-negative Staphylococcus activity of ethanolic extracts of propolis from two Brazilian regions and synergism with antimicrobial drugs by the E-test method

Propolis is a natural resinous substance collected by bees from vegetal sources and its therapeutic properties have been investigated. In this work, we evaluated the inhibitory activity of ethanolic extracts of propolis (EEP) from the Southeast and South of Brazil on coagulase-negative Staphylococcus (CNS) growth as well as the EEP in vitro synergism with antimicrobial drugs by using the diffusion method (E-test). The EEP chemical characteristics (dry weight, pH, flavonoid and phenolic compounds) were determined. Seven drugs were tested, and synergism was observed between three drugs and Southeast EEP, six drugs and South EEP, and one drug and ethanol control. Ethanolic extracts of propolis from the South of Brazil presented the greatest flavonoid content and synergism rate, while EEP from the Southeast presented the greatest anti-CNS activity and phenolic compound content. Results showed the correlation among anti-CNS activity, synergism rate and chemical characteristics of propolis.

Suplementação nutricional com antioxidantes naturais: efeito da rutina na concentração de colesterol-HDL

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Mode of Peroxisome Proliferator-Activated Receptor gamma Activation by Luteolin

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Free radical scavenging activity of Pterogyne nitens Tul. (Fabaceae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Evaluation of Antioxidant Capacity and Synergistic Associations of Quinonemethide Triterpenes and Phenolic Substances from Maytenus ilicifolia (Celastraceae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Tetraflavonoid and biflavonoids from Aristolochia ridicula

Biflavones, a chalcone-flavone, and a tetraflavonoid with a new carbon skeleton were isolated from the leaves of Aristolochia ridicula. Their structures were determined by chemical derivatizations and spectrometric analyses. (c) 2008 Elsevier Ltd. All rights reserved.

Acetylcholinesterase Inhibitory Pyridine Alkaloids of the Leaves of Senna multijuga

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

An LC-DAD Fingerprinting Method for Alkaloids, Flavonoids and Styrylpyrones from Cryptocarya mandioccana

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

High-Performance Liquid Chromatographic Quantification of Flavonoids in Eriocaulaceae Species and Their Antimicrobial Activity

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Antioxidant flavonol glycosides from Nectandra grandiflora (Lauraceae)

O fracionamento cromatográfico do extrato etanólico das folhas de Nectandra grandiflora resultou no isolamento de dois flavonóides glicosilados que apresentaram atividade antioxidante inibindo a oxidação do beta -caroteno em CCDC. As substâncias isoladas tiveram suas estruturas elucidadas através de técnicas espectrométricas de RMN uni- e bidimensional e foram identificadas como 3-O-beta -ramnosy kaempferol and 3-O-beta -ramnosylquercetina.